Existing electromagnetic door openers are, for example, known from German Document DE 10 2004 056 567 A1. The remotely operable electric door opener described also comprises locking members, which during a first stage are form-locked with each other. In a second stage however, the resistance to open the door by force is produced by a rather weak formlock between the locking members, i.e. by a leaf spring hook which is in engagement with the door opener strike bolt. The second stage is thus not very effective as a safeguard against twisting.